{"id":1388,"date":"2026-03-12T06:23:03","date_gmt":"2026-03-12T06:23:03","guid":{"rendered":"https:\/\/razvanvancea.ro\/blog\/?p=1388"},"modified":"2026-03-12T06:32:55","modified_gmt":"2026-03-12T06:32:55","slug":"understanding-js-garbage-collector-how-memory-is-managed","status":"publish","type":"post","link":"https:\/\/razvanvancea.ro\/blog\/2026\/03\/12\/understanding-js-garbage-collector-how-memory-is-managed\/","title":{"rendered":"Understanding JS Garbage Collector – how Memory is managed"},"content":{"rendered":"
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Memory management is one of the most important responsibilities of any programming language runtime. There are programming languages such as C or C++, where the developers manually allocate and free memory. However, Javascript handles memory management automatically through a Garbage Collector (GC).

For most engineers, this process is invisible. However, understanding the garbage collector mechanism is very important. In this article we will see what JavaScript garbage collector is and how it works.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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What is Garbage Collector?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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A garbage collector is a mechanism that automatically frees memory that is no longer being used by a program.<\/p>

When your JavaScript code creates objects, arrays, functions, etc, memory is allocated for them. Over time, some of these values become unreachable, meaning no part of the program can access them anymore.<\/p>

The garbage collector identifies these unreachable values and reclaims their memory, making it available for future allocations.<\/p>

In simple terms:<\/p>

You create objects \u2192 memory is allocated<\/p>

Objects become unused \u2192 memory becomes garbage<\/p>

Garbage collector cleans it up<\/p>

This process prevents programs from consuming more and more memory over time.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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JS Memory Lifecycle<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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The JavaScript memory lifecycle generally follows three steps:

1. Memory Allocation<\/strong><\/p>

Memory is automatically allocated when values are created.<\/p>

Example:<\/p>

let user = {
\u00a0 name: “Razvan”,
\u00a0 age: 21
};<\/p>

Here, memory is allocated for:<\/p>